Sir Stuart Rose may use part of the £34m fortune he amassed during a career running Arcadia and Marks & Spencer to "buy a business" and is plotting a return to the corporate frontline.

"The government says we can't afford to retire, and I don't want to," said Rose, 63, who stepped down as Marks & Spencer chairman in January last year, and is looking for new directorships as he approaches the end of his term on the Land Securities board.

Having earned £25m from the sale of his shares in Arcadia during Sir Philip Green's 2002 buyout, and exited Marks & Spencer with £5m in shares, he could afford to retire in comfort – but he has other plans.

"I've been an employee all my life. Would I wish, if I could rewind it, to have gone down a different route? Possibly, but I've had a great time. Anyway I'm not ruling it out; I could still buy a business."

Rose was speaking ahead of a presentation on Wednesday at which he hoped to persuade 150 retailers to accept payments via mobile phones. The event in London was organised by Mobile Money Network, a smartphone payment technology group that Rose chairs.

He brushed aside speculation that he could front a bid for Home Retail Group, whose Argos and Homebase outlets are suffering falling sales. Rose headed Argos during its takeover by Great Universal Stores, and is a member of the advisory board of Bridgepoint, the private equity owner of sandwich chain Pret A Manger, which, it has been suggested, is planning a raid on HRG.

"I wouldn't hold your breath," he said. "There's other places I could have more fun. I was the chief executive once, I've been there. My recommendation to anybody is don't go backwards."

Rose has said he is looking for a chairmanship but did not rule out a return to a full-time post. Asked about what he would consider, he said: "I wouldn't necessarily limit myself to retail. Brands, consumerism, anything that is consumer-facing.

'I want to have fun'

"My four criteria: I don't want to work with people I don't like; I don't want to work in a business I either don't like or don't understand; I don't want to work for nothing unless I choose to, and I do a fair amount of that already; and I want to have some fun."

Mobile Money Network is owned by Carphone Warehouse, Visa and mobile software firm Monitise, and launched its first product, the Simply Tap payment app for smartphones, in November. In the runup to Easter, it was used to sell 4,000 Thornton's chocolate eggs for 1p: about 200 sales were from people who had seen one of four outdoor advertisements in London; the rest came as word of mouth spread the promotion codes on platforms such as Twitter.

Thornton's, Carphone Warehouse and Liam Gallagher's clothing brand Pretty Green have signed up; HMV, Thomas Pink and Debenhams are considering it; and by the end of 2012 the aim is to have several hundred businesses using the service for a small fee per transaction. The software lets users who have registered their card details take a photo from their phone of an advert or a QR code – barcodes made of dots rather than lines – then tap a "buy" button on their screen. The codes will feature on magazine, poster or broadcast ads, online and in shops.

With rival mobile wallets under development from Google, Paypal and mobile phone companies – the O2 network's payment app moves from trial to public this week – Rose warned retailers that it is only a matter of time before every outlet, be it online or on the high street, will have to accept phone payments.

"If you are not online, people look at you askance," he said. "I think in three to four years' time people will look equally askance at you if you haven't got the ability for consumers to buy what they want, where they want and how they want."

He said shops have dragged their feet. "The people who are slowest to embrace this are the retailers, whether that is because they are very busy with the recession, or they just haven't noticed it yet – both of which are bad reasons."

While the internet forced traditional book and record stores out of business and has damaged electricals outlets such as Comet and Dixons, Rose does not believe mobile shopping need be a threat to retailers: "If you are going to be a fully successful, fully integrated multichannel retailer of the 21st century, you have to have everything; bricks and mortar are not going to disappear."

To prove his point, he jumped up and flashes his Nike "FuelBand" – a rubber-coated bracelet that measures the number of steps taken and calories burned by its wearer.

Rose bought the gadget at the fashionable Boxpark retail arcade, which is constructed of converted shipping containers, in the trendy Hoxton district of London; the bracelet is only available from a limited number of outlets. He believes bricks-and-mortar retailers, if they innovate like the Boxpark merchants who persuaded him to spend £150 on what is essentially a pedometer, still have a future.

"Look at the success of the regeneration of Stratford: Westfield is mobbed," he said. "I was a bit sceptical: I signed on the lease for Marks & Spencer and I bit my lip when I did it, and that was five or six years ago. Now I'm bloody glad I did. It's one of their best-performing stores."